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Making a 1200 X 1600 background

Jul 10, 2012, 00:44
Post: #1
Making a 1200 X 1600 background
Hi guys. First post here so please take it easy on me! I have an image that is a cellphone picture of a magazine picture. It is 1952 X 3264 pixels tall and skinny. It is mostly blackish but has a red line drawing in it.
I would like to make a layer(?) that is 4352 X 3264 (4x3 ratio) that is all black then put the original image on it (as a different layer?). After that I would like to put a very light smoky-haze over it all. Lastly resize it to 1200 X 1600 and reduce the file size to a reasonable size.
I am very new at this so I need a good step by step or link to a good tutorial. Thanks in advance for any and all help.
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Jul 10, 2012, 08:27
Post: #2
RE: Making a 1200 X 1600 background
Your first job is to cut out the cellphone from its background. Given that it is a rather regular shape, the best tools for this is the Path selection, explained here:

http://www.gimp.org/tutorials/Bezier_Selections/

It generates paths that you will find and manipulate here:

http://docs.gimp.org/en/gimp-path-dialog.html

Then:
- you use the path editor to make a path that follows the outline of the phone as accurately as possible. The less points you use, the easier it is to make it smooth ; You sort of need to find the proper balance between accuracy and smoothness, You should certainly need less than 30 points. Since that's you first you are going to sweat over this (about one hour, I would say), because your fingers will have to learn Smile (once you know you do a pretty good job in two minutes). You can find demo videos on Youtube if that helps, but these usually show everything working OK, not how you recover from your mistakes Smile
- at that point you can save your image as an XCF file (Gimp native format)
- in the Paths list: right click the path you created and "Path to selection", you will get a moving dotted line around your phone (a.k.a. the "marching ants) indicating the selection
- open the Layers list (ctrl-L): you will find your image (called "Background unless you changed it already). Right click -> "Add alpha channel" (this allows it to be transparent)
- then back to the main image window:
- "Select/Invert": the selection was on the phone, now it's everything outside the phone
- "Select/clear" or [Delete] key; the background disappears and is replaced by a checkboard which is actually the "canvas" (more or less the virtual bench where you put your layers to work on them....)
- Save the result as XCF again
- call here for further instructions.

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Jul 10, 2012, 21:06
Post: #3
RE: Making a 1200 X 1600 background
I was expecting some big hairy to-do. Was very easy. I was done in about a minute.
I got the image on a background layer and the checkerboard background.
I'm following your advice but would venture to guess the next step would be to create a fully black background with a size of 4352X 3264 or scale the image to fit in a 1200 X 1600 screen. Is this correct?

I appreciate the quick response. Thanks greatly.
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Jul 10, 2012, 22:50
Post: #4
RE: Making a 1200 X 1600 background
Stil with the cell phone image:

- "Image/Canvas size" and give a new size for your canvas ("unchain" height and width) (for instance 4352x3264). You can click the "Center" button to center the cell phone layer
- Set foreground or background color to the cpolor you want to you background
- Ctrl-Shift-N or 'Layer/New layer" to create a new layer. Pick the fill color
- In the Layers list, drag it under the cellphone layer
- If you want so scale the complete image a specific scale, use "Image/Scale image"
- If you want to scale the cell phone "Layer/Scale layer" or the scale tool.
- In both cases you can only scale down if you want clean results.
- If you find the 4352x3264 is too big for you cell phone image, you can crop (Crop) the image around your cell phone.

Try to plan ahead because all the scale operation involve interpolating pixels so they degrade image quality a bit. Not a problem for the first one but the accumulation of such operations eventually blurs the image.

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Jul 11, 2012, 01:01
Post: #5
RE: Making a 1200 X 1600 background
Got up to speed with your help. The image now has a dark grey (black) background that doesn't quite match the image back ground. Tried to use smudge but found out it wouldn't go past the layer border. Played around a bit and saved it as JPG to flatten it. The smudge did work properly, getting rid of the hard line between what was the layers.
I also scaled the image to 1200 X 1600 but found it was too small to do fine work on so I unscaled it. Scaling will be my LAST step.
So now I'm looking for a smoke effect to kinda mystify the total image. Do I find a picture on the net to do the same steps to or can you show me how to do it manually?

Thanks again for your help and quick replies.
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Jul 11, 2012, 06:31
Post: #6
RE: Making a 1200 X 1600 background
(Jul 11, 2012 01:01)Darth Yoda Wrote:  Got up to speed with your help. The image now has a dark grey (black) background that doesn't quite match the image back ground. Tried to use smudge but found out it wouldn't go past the layer border. Played around a bit and saved it as JPG to flatten it. The smudge did work properly, getting rid of the hard line between what was the layers.
I don't quite see what you have... looks like the background of the cellphone wasn't completely removed (the pixels aren't fully transparent). Use the Pointer dialog ("Windows/Dockable dialogs/Pointer"), keep only the cellphone layer visible, and explore the background with the pointer. It should says alpha=0 where the layer looks transparent.

(Jul 11, 2012 01:01)Darth Yoda Wrote:  I also scaled the image to 1200 X 1600 but found it was too small to do fine work on so I unscaled it. Scaling will be my LAST step.
So now I'm looking for a smoke effect to kinda mystify the total image. Do I find a picture on the net to do the same steps to or can you show me how to do it manually?

Thanks again for your help and quick replies.
Try Filter/Render/Clouds/Fog and give it a blueish tint (this filter is only available if your Gimp setup includes Python)

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Jul 11, 2012, 22:19
Post: #7
RE: Making a 1200 X 1600 background
I didn't crop the cellphone picture tightly due to a hazy effect around it so it left a small light grey area around the phone. I tried to smudge it but the effect wasn't quite right. So I jgp'd it and played around. I still have the xcf too.

I play with the smoke on both pix and see what happens. Again thanks for your time.
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Jul 11, 2012, 22:21
Post: #8
RE: Making a 1200 X 1600 background
How do I go about applying Python if needed?
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